318 LA rebuild after losing a valve seat

[Righty Tighty]

So, pistons are installed. However, the crank is so tight I can’t turn it. When I say that, I mean I’m trying so hard I’m afraid the stand is gonna break. I’ve used lots of lube, haven’t torqued the studs yet. They’re barely hand tight. I’m just trying to turn the crank to make sure everything is kosher. Anyone have any thoughts?

 

[383Scampman]

I don't want to get into this discussion with all those experts out there . If the crank doesn't turn you 've gotta find out why . The mains should be torqued before the rods go in . The end play should be checked and the real seal installed . did you check your bearing clearances ? I suggest you pull the rods and see if it turns . The seal will offer some resistance . torque mains one at a time . If it binds up STOP something is wrong . If stuck you must find out why before going forward . Each main torqued must not bind the crank . Center the thrust bearing before final torqueing , check end play . If all is good , add one rod at a time and rotate to check for binding . If any rods bind STOP and find out why . Check , check , clean , clean . You may have a bearing on backwards or upside down . Bad clearances , a bent crank lots of things . good luck and don't give up . We're here to help .

 

[Righty Tighty]

I don't want to get into this discussion with all those experts out there . If the crank doesn't turn you 've gotta find out why . The mains should be torqued before the rods go in . The end play should be checked and the real seal installed . did you check your bearing clearances ? I suggest you pull the rods and see if it turns . The seal will offer some resistance . torque mains one at a time . If it binds up STOP something is wrong . If stuck you must find out why before going forward . Each main torqued must not bind the crank . Center the thrust bearing before final torqueing , check end play . If all is good , add one rod at a time and rotate to check for binding . If any rods bind STOP and find out why . Check , check , clean , clean . You may have a bearing on backwards or upside down . Bad clearances , a bent crank lots of things . good luck and don't give up . We're here to help .

Thanks. Mains were torqued and the crank spun nicely. #1 and 2 pistons felt tight, but then again I don’t know how tight it should be. I thought I could be efficient and install all pistons after 1 and 2 went in, then torque. I’m going to take everything apart tomorrow and start over.

The rods were checked for straightness at the shop prior to install, so I don’t think it’s a bent rod. The rings are supposedly pre-gapped, but I will double check tomorrow. The space between caps is .002, and the space between rod caps/main caps is .0015 to 002. I’m not sure what the specs are, need to check.

Is there such a thing as using too much assembly lube on bearings? I gobbed it on pretty good, thinking excess would squeeze out.

Also, does anyone know if the journal widths are different from the 71 to the 73 crank?

 

[Righty Tighty]

Also, what exactly do you mean by having a bearing upside down? I understand the possibility of having a cap backwards, but are the halves of the bearings specific to cap/rod?

 

[George Jets]

Yes install one rod at a time and make sure the crank turns free, then go on to the next.

Make sure to lube the cylinder walls, pistons and rings with engine oil before assembly.

May want to take one of the top piston rings and slide it into the cylinder bore and make sure it has an end gap so it is not tight.

Fresh bore job, new ring set, new pistons. Have to check and measure things so it all works together as planned. Things can go wrong, wrong parts recieved, etc . . .

 

[George Jets]

Also, what exactly do you mean by having a bearing upside down? I understand the possibility of having a cap backwards, but are the halves of the bearings specific to cap/rod?

Yes bearing in upside down or backwards, little knotches in the bearings go into the casting holes. As you probably know.

Was your crank turned .010 / .010 and verify your bearings are .010 sized too.

Being your rod caps are loose and lubed, would be guessing your pistons and cylinders are dry causing the tightness ??

A place to start.

 

[krazykuda]

So, pistons are installed. However, the crank is so tight I can’t turn it. When I say that, I mean I’m trying so hard I’m afraid the stand is gonna break. I’ve used lots of lube, haven’t torqued the studs yet. They’re barely hand tight. I’m just trying to turn the crank to make sure everything is kosher. Anyone have any thoughts?

Thanks. Mains were torqued and the crank spun nicely. #1 and 2 pistons felt tight, but then again I don’t know how tight it should be. I thought I could be efficient and install all pistons after 1 and 2 went in, then torque. I’m going to take everything apart tomorrow and start over.

The rods were checked for straightness at the shop prior to install, so I don’t think it’s a bent rod. The rings are supposedly pre-gapped, but I will double check tomorrow. The space between caps is .002, and the space between rod caps/main caps is .0015 to 002. I’m not sure what the specs are, need to check.

Is there such a thing as using too much assembly lube on bearings? I gobbed it on pretty good, thinking excess would squeeze out.

Also, does anyone know if the journal widths are different from the 71 to the 73 crank?

Install the pistons two at a time in opposite cylinders... Have the rod journal on the crank in the down position when installing the pistons...

Have you plastic gauged the bearings to make sure that the clearances are good???

As you install the pistons two at a time, you can see how hard the crank is to turn as you go... By the time you get to 6 and then 8 pistons, you should need to have a wrench on the crank to turn it... If it is too tight to turn, then back off the rod caps and loosen the caps two at a time and then try to turn the crank... When you get to the ones where the crank is easier to turn, then look at those two rods and caps carefully...

PS: Make sure that you have the bearings clean and the bores in the rod that the bearings go in absolutely clean... I've seen a small spec of dirt or piece of fuzz get on a bearing or behind one and make it tight and hard to turn... If that happens, you should see a shiny spot on the bearing surface that contacts the crank if that is what caused it to be tight and you were able to turn it with a wrench...

Clean both sides of the rod bore for the bearing with a tack cloth before installing the bearings, and then tack cloth the bearings and then the crank bearing journals on the crank before installing the pistons... Make sure that your hands are clean and free of dirt, even if you have to keep washing them after each set of pistons...


Make sure that the rings are not overlapped also....

Then make sure the the bearings don't get knocked out of whack and overlap when you are installing them - it's happened to me before... make sure that the bearings are properly seated in the bores and that they butt up to each other properly when the cap mates to the rod...

 

[Righty Tighty]

Yes bearing in upside down or backwards, little knotches in the bearings go into the casting holes. As you probably know.

Was your crank turned .010 / .010 and verify your bearings are .010 sized too.

Being your rod caps are loose and lubed, would be guessing your pistons and cylinders are dry causing the tightness ??

I installed the bearings with the tangs oriented correctly, though I did notice one or two sat just proud of the cap or rod, maybe .020 or so. The crank I have is .040 under, so I ordered .040 under bearings. All journals would be .040 under, right? not just the mains?

I did lube the pistons and cylinders.

Install the pistons two at a time in opposite cylinders... Have the rod journal on the crank in the down position when installing the pistons...

Have you plastic gauged the bearings to make sure that the clearances are good???

As you install the pistons two at a time, you can see how hard the crank is to turn as you go... By the time you get to 6 and then 8 pistons, you should need to have a wrench on the crank to turn it... If it is too tight to turn, then back off the rod caps and loosen the caps two at a time and then try to turn the crank... When you get to the ones where the crank is easier to turn, then look at those two rods and caps carefully...

PS: Make sure that you have the bearings clean and the bores in the rod that the bearings go in absolutely clean... I've seen a small spec of dirt or piece of fuzz get on a bearing or behind one and make it tight and hard to turn... If that happens, you should see a shiny spot on the bearing surface that contacts the crank if that is what caused it to be tight and you were able to turn it with a wrench...

Clean both sides of the rod bore for the bearing with a tack cloth before installing the bearings, and then tack cloth the bearings and then the crank bearing journals on the crank before installing the pistons... Make sure that your hands are clean and free of dirt, even if you have to keep washing them after each set of pistons...


Make sure that the rings are not overlapped also....

Then make sure the the bearings don't get knocked out of whack and overlap when you are installing them - it's happened to me before... make sure that the bearings are properly seated in the bores and that they butt up to each other properly when the cap mates to the rod...

Thanks KK, I did all of that regarding cleanliness. I plasti gauged the mains, not the rods though. I'll be doing that tomorrow. Something is telling me it's either tight rings or bearings. Could too much assembly lube cause this?

 

[krazykuda]

I installed the bearings with the tangs oriented correctly, though I did notice one or two sat just proud of the cap or rod, maybe .020 or so. The crank I have is .040 under, so I ordered .040 under bearings. All journals would be .040 under, right? not just the mains?

Yes, the machine shop should have made all of the journals the same size....

The bearing shells should be flush with each side of the cap, not proud - that could make them tight...

 

[krazykuda]

I did lube the pistons and cylinders.



Thanks KK, I did all of that regarding cleanliness. I plasti gauged the mains, not the rods though. I'll be doing that tomorrow. Something is telling me it's either tight rings or bearings. Could too much assembly lube cause this?

I doubt that it's too much assembly lube... If use too much lube - it will just squish out when you assemble and tighten the parts...

It's better to have too much lube, than too little... (That's what she said...)

 

[Righty Tighty]

The crank I bought as a reman .040 under. Not quite sure why I did that, maybe just because the old crank was .040? Newbie mistake.

I'm going to give a closer look at the bearings tomorrow.

 

[krazykuda]

Thanks KK, I did all of that regarding cleanliness. I plasti gauged the mains, not the rods though. I'll be doing that tomorrow. Something is telling me it's either tight rings or bearings. Could too much assembly lube cause this?

Plastic gauge the rods and see what it says... If there's too much or too little clearance it will show up by not getting the proper clearance..

 

[krazykuda]

The crank I bought as a reman .040 under. Not quite sure why I did that, maybe just because the old crank was .040? Newbie mistake.

I'm going to give a closer look at the bearings tomorrow.

You should be able to rotate the crank by hand with just the crank in, and after installing up to 4 pistons, after that it starts getting too tight to turn by hand and you will need a socket and ratchet to rotate it...

 

[krazykuda]

The crank I bought as a reman .040 under. Not quite sure why I did that, maybe just because the old crank was .040? Newbie mistake.

I'm going to give a closer look at the bearings tomorrow.

Did the reman crank come with bearings, or did you order them separately???

 

[Righty Tighty]

You should be able to rotate the crank by hand with just the crank in, and after installing up to 4 pistons, after that it starts getting too tight to turn by hand and you will need a socket and ratchet to rotate it...

The crank rotated smooth as silk by hand before the pistons. After the first and second I noticed a marked increase in resistance.

The reman didn't come with bearings, I ordered them separately.

 

[krazykuda]

The crank rotated smooth as silk by hand before the pistons. After the first and second I noticed a marked increase in resistance.

The reman didn't come with bearings, I ordered them separately.

It sounds like the bearings are your issue... Check to make sure both ends of the bearing shells sit flush when you install them in the rod and cap... If they stick up too high, that can cause problems...

 

[krazykuda]

The crank rotated smooth as silk by hand before the pistons. After the first and second I noticed a marked increase in resistance.

The reman didn't come with bearings, I ordered them separately.

Did you have the crank bores in the rods redone, or just use them as is...

I get new rod bolts and have the crank bores of the rods remachined after installing the new bolts, that way the cap and rod are properly aligned and the bores are fresh and round to spec...

You need to make sure not to torque the rod bolts too much - 5 times max, to prevent stretching them too much and weakening them...

 

[sireland67]

Do not assume the mains and rods had the same taken off.
The crank in the 318 I just built there is a .010” difference.
I would borrow/buy a caliper and measure what you have.

 

[pt70]

The number on the crank from post #40 did not show up from my book. But your crank is different than a 1970 crank from a 318 with the small rods.

You mentioned .040 bearings but a .030 under crank in a previous post?

Each connecting rod cap MUST be matched to its own connecting rod. Each rod and cap is numbered on the side of the big end of the rod and cap. The numbers go outward. Check your numbers. With the block upside down, loosen all rod nuts a half a turn. The crank should turn by using the harmonic balancer. Remove a rod cap, put a piece of 3/8'' rubber gas line over the bolts to protect the crank surface, turn the crank to push the rod down, slide out the bearing shell, and push out the piston and rod with a block of wood. Slide the bearings back on, and assemble the rod 'sideways' on [out of] the block. Snug the cap nuts. Rod move smoothly? ---- Tighten the nuts. Still smooth? Remove the rod assy. Remove all pistons. Check the ring gap when the pistons are on their way out.

Reassemble only after you've found a problem.

 

[Righty Tighty]

You mentioned .040 bearings but a .030 under crank in a previous post?

That was a typo, I think I had .040 in my head because the cylinders are .040 over. (I did go and double check when I read your post though...)

Did you have the crank bores in the rods redone, or just use them as is...

I get new rod bolts and have the crank bores of the rods remachined after installing the new bolts, that way the cap and rod are properly aligned and the bores are fresh and round to spec...

You need to make sure not to torque the rod bolts too much - 5 times max, to prevent stretching them too much and weakening them...

The machine shop did the bores, and said one was out of round, so he fixed that. I'm using brand new rod bolts. I'm definitely going to have a look at the bearings and caps.

 

[nm9stheham]

Do not assume the mains and rods had the same taken off.
The crank in the 318 I just built there is a .010” difference.
I would borrow/buy a caliper and measure what you have.

This.... do NOT assume the rods and mains are turned down the same amount. But if 1 and 2 turned with some mild resistance, then it sounds basically OK. Still need to apply plastigage to make sure.

And yes, there have been reports of too much assembly lube if it is the greasy paste stuff; don't use that. Motor oil is just fine as an assembly lube. You ought to be priming the engine anyhow.

Good info and advice on the rest of the posts: rod cap backwards, plastigage, ring gaps, loosen or install one at a time to find any issue.

 

[nm9stheham]

The number on the crank from post #40 did not show up from my book. But your crank is different than a 1970 crank from a 318 with the small rods.

PN shows up here for '71-'91 LA 318. UP to '73 used the lighter rods IIRC. I do not know of any break in crank PN from '70 to '71....so I suspect a typo in the Crankshaft Supply listing....??? Big end widths of the rods did not change. Same rod bearings used from '57 to '91.
http://crankshaftsupply.com/crankcatalog.htm

And edit to add: The AERA crank manual does not show a year break in cranks between '70 and '71 for the 318's.... so, yes, a typo on the CS site catalog.

 

[Righty Tighty]

This is the lube I’m using. A little thicker than toothpaste. Anyhow, it’s all coming apart today.

I did notice something odd when I first tore apart the engine, some of the rods were stamped with numbers that didn’t match the cylinder they came out of. I kept them in order according to how they came out, not the numbers stamped. And not all of the rods are marked. I think someone had this engine apart and carelessly put it back together at one point.

 

[nm9stheham]

Yeah, don't use that stuff IMHO! Some fresh motor oil will do. Same on the pistons and rings. Read up on how to prime the engine's oiling system once assembled. It's a VERY good thing to do.

Yes, and you could have some re-manufactured rods there. Anything is possible. The order of the rods is not really important as far as I have ever known. The direction of the rods bearing tang notches (relative to each other and to the block) and oil squirt holes IS important.

Mixing up unmakred rod caps to rods is not hard to do. As pt70 sez, they cannot be mixed.... at all. Next time you take apart an engine, if a rod is not marked, then mark it yourself. HF has some cheap number stamp sets.... which I assume will not dull with the fist use LOL.

 

[krazykuda]

View attachment 1715474064 This is the lube I’m using. A little thicker than toothpaste. Anyhow, it’s all coming apart today.

I did notice something odd when I first tore apart the engine, some of the rods were stamped with numbers that didn’t match the cylinder they came out of. I kept them in order according to how they came out, not the numbers stamped. And not all of the rods are marked. I think someone had this engine apart and carelessly put it back together at one point.

The stamped order on the rods is not as important as the orientation of the rod... THe top of the piston goes toward the center of the engine (or top of the cylinder) and the anchor slots go toward the outside...